Simopoulos A P
The Center for Genetics, Nutrition and Health, Washington, DC 20009, USA.
Biomed Pharmacother. 2002 Oct;56(8):365-79. doi: 10.1016/s0753-3322(02)00253-6.
Several sources of information suggest that human beings evolved on a diet with a ratio of omega-6 to omega-3 essential fatty acids (EFA) of approximately 1 whereas in Western diets the ratio is 15/1-16.7/1. Western diets are deficient in omega-3 fatty acids, and have excessive amounts of omega-6 fatty acids compared with the diet on which human beings evolved and their genetic patterns were established. Excessive amounts of omega-6 polyunsaturated fatty acids (PUFA) and a very high omega-6/omega-3 ratio, as is found in today's Western diets, promote the pathogenesis of many diseases, including cardiovascular disease, cancer, and inflammatory and autoimmune diseases, whereas increased levels of omega-3 PUFA (a low omega-6/omega-3 ratio) exert suppressive effects. In the secondary prevention of cardiovascular disease, a ratio of 4/1 was associated with a 70% decrease in total mortality. A ratio of 2.5/1 reduced rectal cell proliferation in patients with colorectal cancer, whereas a ratio of 4/1 with the same amount of omega-3 PUFA had no effect. The lower omega-6/omega-3 ratio in women with breast cancer was associated with decreased risk. A ratio of 2-3/1 suppressed inflammation in patients with rheumatoid arthritis, and a ratio of 5/1 had a beneficial effect on patients with asthma, whereas a ratio of 10/1 had adverse consequences. These studies indicate that the optimal ratio may vary with the disease under consideration. This is consistent with the fact that chronic diseases are multigenic and multifactorial. Therefore, it is quite possible that the therapeutic dose of omega-3 fatty acids will depend on the degree of severity of disease resulting from the genetic predisposition. A lower ratio of omega-6/omega-3 fatty acids is more desirable in reducing the risk of many of the chronic diseases of high prevalence in Western societies, as well as in the developing countries, that are being exported to the rest of the world.
多种信息来源表明，人类在进化过程中所食用的饮食中，ω-6与ω-3必需脂肪酸（EFA）的比例约为1，而西方饮食中的这一比例为15/1至16.7/1。与人类进化及遗传模式形成时的饮食相比，西方饮食中ω-3脂肪酸不足，而ω-6脂肪酸过量。如当今西方饮食中所发现的，过量的ω-6多不饱和脂肪酸（PUFA）以及极高的ω-6/ω-3比例会促进包括心血管疾病、癌症以及炎症和自身免疫性疾病在内的多种疾病的发病机制，而ω-3 PUFA水平的升高（低ω-6/ω-3比例）则具有抑制作用。在心血管疾病的二级预防中，4/1的比例与总死亡率降低70%相关。2.5/1的比例可降低结直肠癌患者的直肠细胞增殖，而相同量的ω-3 PUFA在4/1的比例时则没有效果作用。乳腺癌女性中较低的ω-6/ω-3比例与风险降低相关。2 - 3/1的比例可抑制类风湿性关节炎患者的炎症，5/1的比例对哮喘患者有有益影响，而10/1的比例则会产生不良后果。这些研究表明，最佳比例可能因所考虑的疾病而异。这与慢性病是多基因和多因素的这一事实是一致的。因此，ω-3脂肪酸的治疗剂量很可能取决于由遗传易感性导致的疾病严重程度。在降低西方社会以及正在向世界其他地区输出的发展中国家普遍存在的许多慢性病风险方面，较低的ω-6/ω-3脂肪酸比例更为可取。
